Solar battery

ABSTRACT

A diode-incorporated solar battery, which is intended to minimize an increase in production cost and a decrease in reliability that are involved in incorporating diodes into the solar battery, and to reduce the area of the surface electrodes of the solar battery so as to increase the electric power generation of the solar battery, wherein to this end, a connecting metal fixture for interconnecting solar cells has added thereto projection for parallel-connecting the solar cells and diodes.

TECHNICAL FIELD

[0001] The present invention relates to a solar battery with built-indiodes.

BACKGROUND ART

[0002] The connection structure disclosed in U.S. Pat. No. 6,034,322 isknown as a technique for mounting a diode to a solar battery cell. A topview of a conventional solar battery cell with built-in diode is shownin FIG. 9 and a cross-sectional view of the conventional solar batterycell with built-in diode is shown in FIG. 10. To effectively utilize adisc-shaped crystal substrate, a triangular planar diode is mounted atthe corner crop provided in the solar battery cell.

[0003] In the figure, a solar battery cell 1 has a beveled edge whereone corner has been partially removed, and a diode 2 is provided at thesame position as the removed edge. In this solar battery cell withbuilt-in diode, a diode connection bracket 3 a is respectively connectedto a front surface electrode 4 of the solar battery cell 1 and to afront surface electrode 6 of the diode 2, and a diode connection bracket3 b is respectively connected to a rear surface electrode 5 of the solarbattery cell 1 and to a rear surface electrode 7 of the diode 2 using amethod such as parallel gap welding.

[0004] This electrically connects the solar battery cell 1 and the diode2 in parallel so that damage to the solar battery cell 1 can beprevented even if a reverse voltage is applied to the solar battery cell1.

[0005] Furthermore, although the voltage generated from one solarbattery cell differs according to the type of the solar battery cell, ithas at the most a range of 0.5 to 3 V. Thus, it is common to obtain apredetermined working voltage by configuring a circuit to connect aplurality of solar battery cells in series. In an ordinary solar batterycell circuit, a plurality of solar battery cells are connected in seriesby connecting solar battery cell brackets to the front surfaces and therear surfaces of adjacently positioned solar battery cells.

[0006] Therefore, in the conventional solar battery cell with built-indiode, in addition to the solar battery connection bracket forconnecting each solar battery cell in series, two diode connectionbrackets are necessary for connecting the diode 2 in parallel.

[0007] Since the diode connection bracket, which has a characteristicshape with a function only to connect the solar battery cell and diodeas described above, is used to connect the solar battery cell and thediode in the conventional solar battery cell with built-in diode, thelarger number of connection points increases the time required foradding a diode to the solar battery cell, and the reliability decreases.

[0008] In particular, the front surface of the solar battery cell isprovided with rectangular front surface electrodes near the periphery ofthe solar battery cell, and making connections, such as through welding,to match the positions of the front surface electrodes is difficult, andthe assembly time increases due to the larger number of connectionpoints.

[0009] Furthermore, simultaneously connecting the front and rearsurfaces of the diode and the front and rear surfaces of the solarbattery cell with connection brackets 3 a, 3 b was difficult. Anotherconcern was the increase in the number of parts and part types and theincrease in the cost of materials that resulted from the increase in thenumber of connection points.

[0010] Moreover, the solar battery array has become significantly largeso that low efficiency, low cost silicon solar battery cells are notused any longer. As a result, gallium arsenide based solar battery cellsof the high efficiency III-V group (of the periodic table) must beconsidered. Regarding these solar battery cells in terms of initialmanufacturing cost, the solar battery cells forming the base are high incost so that it is necessary to utilize the most active area of theblank cells.

[0011] In addition, another problem was that adding an electrode forconnection with the diode to the front surface of the solar battery celldecreases the area contributing to power generation so that the amountof generated electricity decreases. The power loss in generatedelectricity accompanying the addition of electrodes is about 0.1% of thetotal generated electricity of one 50 mm square solar battery cell(generated electricity of about 1 W). If 100,000 of these solar batterycells are used as a solar battery for mounting in a satellite togenerate electricity, a power loss of about 100 W results, which is anamount that cannot be ignored in the supply of power to the satellite.

DISCLOSURE OF INVENTION

[0012] It is therefore an object of this invention to solve the relevantproblems by reducing the increase in manufacturing cost and the drop inreliability accompanying the addition of the diode to the solar batterycell, and by increasing the amount of generated electricity of the solarbattery cell through the reduction of the front surface electrode areaon the solar battery cell.

[0013] The solar battery relating to the present invention comprisesplanar first and second solar battery cells, a diode connected inparallel with the first solar battery cell, a solar battery connectionbracket for connecting a front surface electrode provided on a frontsurface of the first solar battery cell and a rear surface electrodeprovided on a rear surface of the second solar battery cell and a frontsurface electrode provided on a front surface of the diode, and a diodeconnection bracket for connecting a rear surface electrode provided on arear surface of the first solar battery cell and a rear surfaceelectrode provided on a rear surface of the diode. The first solarbattery cell and the second solar battery cell are planar solar batterycells that are substantially rectangular having four corners, at leastone of the corners has a partially removed beveled edge, and the diodeis positioned adjacent to the beveled edge in the area of the removedcorner.

[0014] Furthermore, the solar battery connection bracket has at leastone rectangular first connector for connecting the front surfaceelectrode of the first solar battery cell and the rear surface electrodeof the second solar battery cell, at least one rectangular secondconnector for connecting the rear surface electrode of the second solarbattery cell and the front surface electrode of the diode, and at leastone rectangular third connector for connecting the rear surfaceelectrode of the first solar battery cell and the rear surface electrodeof the diode. The first connector, the second connector, and the thirdconnector may be connected on the side opposite to the light receivingsurface of the solar battery cell.

[0015] Furthermore, the solar battery relating to the present inventioncomprises planar first and second solar battery cells, a diode connectedin parallel with the first solar battery cell, a first solar batteryconnection bracket for connecting a front surface electrode provided ona front surface of the first solar battery cell and a rear surfaceelectrode provided on a rear surface of the second solar battery cell, asecond solar battery connection bracket for connecting-the rear surfaceelectrode of the second solar battery cell and a front surface electrodeprovided on the front surface of the diode, and a diode connectionbracket for connecting a rear surface electrode provided on a rearsurface of the first solar battery cell and a rear surface electrodeprovided on a rear surface of the diode. The first solar battery celland the second solar battery cell are planar solar battery cells thatare substantially rectangular having four corners, at least one of thecorners has a partially removed beveled edge, and the diode ispositioned adjacent to the beveled edge in the area of the removedcorner.

[0016] Furthermore, the solar battery relating to the present inventionis formed by positioning in successive adjacency at least two solarbattery cells with built-in diode, which includes planar solar batterycells that are substantially rectangular having four corners with atleast one of the corners having a partially removed beveled edge and thediode positioned adjacent to the beveled edge in the area of the removedcorner, and in which front surface electrodes provided on front surfacesof the solar battery cell and the diode included in one solar batterycell with built-in diode and rear surface electrodes provided on rearsurfaces of the solar battery cell and the diode included in anotheradjacent solar battery cell with built-in diode are connected by onesolar battery connection bracket.

[0017] Furthermore, the solar battery cell relating to the presentinvention is formed by positioning in successive adjacency at least twosolar battery cells with built-in diode, which includes planar solarbattery cells that are substantially rectangular having four cornerswith at least one of the corners having a partially removed beveled edgeand the diode positioned adjacent to the beveled edge in the area of theremoved corner, and in which surface electrodes provided on frontsurface of the solar battery cell included in one solar battery cellwith built-in diode and rear surface electrodes provided on rear surfaceof the solar battery cell included in another adjacent solar batterycell with built-in diode are connected by a solar battery connectionbracket, and a surface electrode provided on the front surface of thediode included in the solar battery cell with built-in diode and rearsurface electrodes provided on rear surfaces of the solar battery celland the diode included in the other adjacent solar battery cell withbuilt-in diode are connected by a diode connection bracket.

[0018] Furthermore, the solar battery connection bracket or the diodeconnection bracket may be made of a material that includes silver.

[0019] Furthermore, the front surface electrode or the rear surfaceelectrode of the solar battery cell, or the front surface electrode orthe rear surface electrode of the diode may include silver.

[0020] Furthermore, the solar battery connection bracket or the diodeconnection bracket may have a bend for a thermal expansion buffer.

[0021] Furthermore, the bends may have a U-shaped structure.

[0022] Furthermore, only one of the corners may have a beveled edge.

[0023] Furthermore, the beveled edge may be formed from an arc.

[0024] Furthermore, the solar battery cell may be cut out from adisc-shaped crystal substrate.

BRIEF DESCRIPTION OF DRAWINGS

[0025]FIG. 1 is a top view of a solar battery in embodiment 1 accordingto the present invention.

[0026]FIG. 2 is a side view of the solar battery in embodiment 1according to the present invention.

[0027]FIG. 3 is a top view of a solar battery in embodiment 2 accordingto the present invention.

[0028]FIG. 4 is a top view of a solar battery in embodiment 3 accordingto the present invention.

[0029]FIG. 5 is a side view of the solar battery in embodiment 3according to the present invention.

[0030]FIG. 6 is a top view of a solar battery in embodiment 4 accordingto the present invention.

[0031]FIG. 7 is a side view of the solar battery in embodiment 4according to the present invention.

[0032]FIG. 8 is a cross-sectional view of a solar battery in embodiment5 according to the present invention.

[0033]FIG. 9 is a top view of a conventional solar battery cell withbuilt-in diode.

[0034]FIG. 10 is a cross-sectional view of the conventional solarbattery cell with built-in diode.

[0035]FIG. 11 shows the shape of a solar battery in embodiment 6according to the present invention.

[0036]FIG. 12 is an assembly diagram of the solar battery in embodiment6 according to the present invention.

[0037]FIG. 13 shows the shape of a solar battery in embodiment 7according to the present invention.

[0038]FIG. 14 is an assembly diagram of the solar battery in theembodiment 7 according to the present invention.

[0039]FIG. 15 shows the shape of the diode used in the presentinvention.

MODE(S) FOR CARRYING OUT THE INVENTION

[0040] The present invention will be described in detail with referenceto the attached drawings.

[0041] Embodiment 1

[0042]FIG. 1 is a top view showing a part of the solar battery inembodiment 1 of the present invention. FIG. 2 is a side view of thesolar battery of FIG. 1 as viewed from the bottom.

[0043] Solar battery cells 1 a, 1 b, 1 c are disposed in the same plane.These solar battery cells 1 a, 1 b, 1 c represent a part of a group ofsolar battery cells disposed in plurality. At least one corner of eachsolar battery cell has a partially removed beveled edge, and triangularplanar diodes 2 a, 2 b are disposed to fit the removed beveled edges.Solar battery cells 1 a, 1 b respectively have front surface electrodes4 a to 4 c and 4 d to 4 f as collector electrodes on the front surface,and rear surface electrodes 7 a, 7 b as collector electrodes on the rearsurface. It is preferable for each of these electrode to be made of amaterial that includes silver and to have a thin layer of gold on thesurface.

[0044] A solar battery connection bracket 8 a has rectangularprotrusions for connecting the front surface electrodes 4 a, 4 b, 4 c ofthe solar battery cell la to the rear surface electrode 5 b of the solarbattery cell 1 b, rectangular protrusions for connecting the rearsurface electrode 5 b of the solar battery cell lb to a front surfaceelectrode 6 a of the diode 2 a, and a comb shape formed from a connectorfor mutually connecting the respective protrusions. A solar batteryconnection bracket 8 b also has a similar shape and structure andconnects the front surface electrodes 4 d, 4 e, 4 f of the solar batterycell 1 b, a rear surface electrode of the solar battery cell 1 c, and asurface electrode 6 b of the diode 2 b.

[0045] If the light receiving surface is the front surface of the solarbattery cell, it is preferable to dispose the connector of the solarbattery connection bracket on the rear surface of the solar battery cellto prevent shadowing of the light receiving surface. Furthermore,although the solar battery cell in the present embodiment has threefront surface electrodes, this is not a limitation of the presentinvention provided at least one surface electrode is available, and thenumber of protrusions on the solar battery connection bracket may beincreased or decreased according to the number of surface electrodes. Itis preferable for the material of the solar battery connection brackets8 a, 8 b to include silver.

[0046] Furthermore, a rear surface electrode 5 a of the solar batterycell 1 a and the rear surface electrode 7 a of the diode 2 a areconnected by the diode connection bracket 3 a, the adjacent solarbattery cell la and the solar battery cell 1 b are connected in seriesby the solar battery connection bracket 8 a, and the solar battery cell1 a and the diode 2 a are connected in parallel by the diode connectionbracket 3 a. In the same manner, the rear surface electrode 5 b of thesolar battery cell 1 b and the rear surface electrode 7 b of the diode 2b are connected by the diode connection bracket 3 b, the solar batterycells 1 b, 1 c are connected in series by the solar battery connectionbracket 8 b, and the diode 2 b is connected in parallel with respect tothe solar battery cell 1 b. It is preferable for the material of thediode connection brackets 3 a, 3 b to include silver.

[0047] According to the description above, it is possible to reduce thenumber of parts by one and the number of connections by one whencompared to the case where diode connection brackets are used torespectively connect the front and rear surfaces of the diodes and thesolar battery cells.

[0048] Embodiment 2

[0049]FIG. 3 is a top view showing a part of the solar battery inembodiment 2 of the present invention.

[0050] As in embodiment 1, the solar battery cells 1 a, 1 b, 1 c aredisposed in the same plane. These solar battery cells represent a partof a group of solar battery cells disposed in plurality. The lower leftcorner of each solar battery cell has a partially removed beveled edge,and triangular planar diodes 2 a, 2 b are disposed to fit the removedparts. The solar battery cells 1 a, 1 b respectively have front surfaceelectrodes 4 a to 4 c and 4 d to 4 f as collector electrodes on thefront surface, and rear surface electrodes generally covering the entirerear surface as collector electrodes on the rear surface.

[0051] The front surface electrodes 4 a, 4 b, 4 c of the solar batterycell la and the rear surface electrodes of the solar battery cell 1 bare connected by solar battery connection brackets 8 b, 8 c, 8 d. Therear electrode of the solar battery cell 1 b is further connected to thefront surface electrode of the diode 2 a by the solar battery connectionbracket 8 a. In the same manner, the front surface electrodes 4 d, 4 e,4 f of the solar battery cell 1 b and the rear surface electrodes of thesolar battery cell 1 c are connected by solar battery connectionbrackets 8 f, 8 g, 8 h, and the rear surface electrode of the solarbattery cell 1 c is further connected to the front surface electrode ofthe diode 2 b by a solar battery connection bracket 8 e.

[0052] The rear surface electrode of the solar battery cell 1 a and therear surface electrode of the diode 2 a are connected by a diodeconnection bracket 3 a. In the same manner, the rear surface electrodeof the solar battery cell 1 b and the rear surface electrode of thediode 2 b are connected by the diode connection bracket 3 b.

[0053] Although each solar battery cell in the present embodiment hasthree surface electrodes, this is not a limitation of the presentinvention provided at least one surface electrode is available, and thenumber of solar battery connection brackets may be increased ordecreased according to the number of surface electrodes. It ispreferable for the material of the solar battery connection brackets 8 ato 8 h and of the diode connection brackets 3 a, 3 b to include silver.

[0054] In the solar battery cell with built-in diode as configuredabove, the adjacent solar battery cells are each connected in series andthe diodes are connected in parallel with each solar battery cell.

[0055] Therefore, in comparison to embodiment 1, there is no need to useconnection brackets having a complex shape (comb) by using thesame-shaped connection brackets 8 a to 8 h to connect the surfaceelectrodes of the solar battery cells and diodes via the rear surfaceelectrodes of adjacent solar battery cells. Only diode connectionbrackets (3 a, 3 b) and solar battery connection brackets (8 a to 8 h)having the same shape (rectangular) but only different lengths are usedso that the types of parts can be reduced.

[0056] According to the description above, by using connection bracketshaving the same shape to connect the front surface electrodes of thesolar battery cells and diodes via the rear surface electrodes ofadjacent solar battery cells, the types of parts can be reduced.

[0057] Embodiment 3

[0058]FIG. 4 is a top view showing a part of the solar battery inembodiment 3 of the present invention. FIG. 5 is a side view of thesolar battery of FIG. 4 as viewed from the bottom.

[0059] Solar battery cells 1 a, 1 b, 1 c are disposed in the same plane.These solar battery cells 1 a, 1 b, 1 c represent a part of a group ofsolar battery cells disposed in plurality. At least one corner of eachsolar battery cell has a partially removed beveled edge, and triangularplanar diodes 2 a, 2 b are disposed to fit the removed beveled edges.Solar battery cells 1 a, 1 b have front surface electrodes 4 a to 4 cand 4 d to 4 f as collector electrodes on the front surface, and rearsurface electrodes 7 a, 7 b as collector electrodes on the rear surface.It is preferable for each of these electrodes to be made of a materialthat includes silver and to have a thin layer of gold on the surface.

[0060] A solar battery connection bracket 8 i has rectangularprotrusions for connecting the front surface electrodes 4 a, 4 b, 4 c ofthe solar battery cell la and the rear electrode 5 b of the solarbattery cell 1 b, rectangular protrusions for connecting the rearsurface electrode 5 b of the solar battery cell 1 b and the frontsurface electrode 6 a of the diode 2 a and the rear surface electrode 7b of the diode 2 b, and a comb shape formed from a connector formutually connecting the respective protrusions. A solar batteryconnection bracket 8 j has a similar shape and structure.

[0061] Although the present embodiment has substantially the same modeas embodiment 1, the difference is that the connection bracket 8 i isused instead of the individually provided solar battery connectionbracket 8 a and the diode connection bracket 3 b in embodiment 1.

[0062] In the solar battery cell with built-in diode as configuredabove, the adjacent solar battery cells are each connected in series andthe diodes are connected in parallel to each solar battery cell.

[0063] According to the description above, by using one solar batteryconnection bracket to perform both functions of connecting in series thesolar battery cells and connecting in parallel the solar battery cellsand diodes, the number of parts further decreases from embodiment 1 byone and the manufacturing process can be simplified.

[0064] Embodiment 4

[0065]FIG. 6 is a top view showing part of the solar battery inembodiment 4 of the present invention. FIG. 7 is a side view of thesolar battery of FIG. 6 as viewed from the bottom.

[0066] Solar battery cells 1 a, 1 b, 1 c are disposed in the same plane.These solar battery cells represent a part of a group of solar batterycells disposed in plurality. The lower left corner of each solar batterycell has a partially removed beveled edge, and the triangular planardiodes 2 a, 2 b are disposed to fit the removed parts. Solar batterycells 1 a, 1 b have front surface electrodes 4 a to 4 c and 4 d to 4 fas collector electrodes on the front surface, and rear surfaceelectrodes generally covering the entire rear surface as collectorelectrodes on the rear surface.

[0067] The front surface electrodes 4 a, 4 b, 4 c of the solar batterycell la and the rear surface electrode 5 b of the solar battery cell lbare connected by solar battery connection brackets 8 b, 8 c, 8 d. Therear surface electrode 5 b of the solar battery cell 1 b and the frontsurface electrode 6 a of the diode 2 a and the rear surface electrode 7b of the diode 2 b are connected by a solar battery connection bracket 8k. A solar battery connection bracket 8 m has a similar structure.

[0068] Although the present embodiment has substantially the same modeas embodiment 2, the difference is that one solar battery connectionbracket 8 k is used instead of the individually provided solar batteryconnection bracket 8 a and the diode connection bracket 3 b inembodiment 2.

[0069] In the solar battery cell with built-in diode as configuredabove, the adjacent solar battery cells are each connected in series andthe diodes are connected in parallel to each solar battery cell.

[0070] According to the description above, the number of parts comparedto embodiment 2 can be further decreased by one.

[0071] Embodiment 5

[0072]FIG. 8 is a cross-sectional view of the solar battery inembodiment 5.

[0073] Although the present embodiment has substantially the same modeas embodiment 1, a support substrate 9 is further fixed with adhesive 10to support the solar battery cells 1 a, 1 b. For reasons of lightnessand durability, the material of the support substrate 9 shouldpreferably be a plastic that is reinforced with carbon fibers or aramidfibers. Furthermore, for reasons of its adhesive properties, adhesion,and thermal conduction, the adhesive 10 should preferably be asilicon-based adhesive.

[0074] Furthermore, the solar battery connection bracket 8 a and thediode connection bracket 3 a of the present embodiment differ from thosein embodiment 1 in terms of their U-shaped bends.

[0075] For example, in the case where the operating temperature range ofthe solar battery cell circuit is wide, such as when mounted in asatellite, the connection points at the solar battery cell 1 a and thesolar battery cell 1 b of the solar battery connection bracket 8 a, andthe connection points at the solar battery cell 1 a and the diode 2 a ofthe diode connection bracket 3 a are subjected to thermal loading due tothe difference in the linear expansion coefficients between the solarbattery connection bracket 8 a and diode connection bracket 3 a havingbase metals of silver and the support substrate 9 of plastic reinforcedwith carbon fibers or aramid fibers.

[0076] However, in the present embodiment, the above-mentioned thermalloading is lowered by providing U-shaped bends as shown in FIG. 8 to thesolar battery connection bracket 8 a and the diode connection bracket 3a and reducing the rigidity of the solar battery connection bracket 8 aand the diode connection bracket 3 a.

[0077] Clearly in the above-mentioned description, it is preferable forthe bends in the solar battery connection bracket 8 a and the diodeconnection bracket 3 a to have the U shape as in the present embodimentfor the reason of ease of machining. However, the present invention isnot limited to this. Any method for reducing the rigidity of the solarbattery connection bracket 8 a and the diode connection bracket 3 a soas to lower the thermal loading on the connection points due to thermalexpansion is sufficient. For example, a bellows shape, a W (or M) shape,or a Z shape is sufficient.

[0078] Furthermore, the bends in the present embodiment can also beapplied to the solar battery connection brackets and the diodeconnection brackets in the other embodiments.

[0079] According to the description above, when the solar battery cellcircuit is used in a wide temperature range, the thermal loading on theconnection points on the solar battery cells and the diodes can belowered so as to improve the reliability of the connections.

[0080] Embodiment 6

[0081] Although there are various manufacturing methods for solarbattery cells, common manufacturing methods include diffusing impuritiesin a disc-shaped crystal substrate (wafer) 12 that is cut out from acylindrical silicon or compound semiconductor crystal material andforming a PN junction surface, or forming a semiconductor layer on acrystal substrate and then forming a PN junction surface.

[0082]FIG. 11 shows the shapes of the crystal substrate 12 and the solarbattery cell 1 when manufacturing rectangular planar solar battery cellsfrom the disc-shaped crystal substrate 12 in embodiment 6 of the presentinvention.

[0083] When cutting out the rectangular planar solar battery cell 1 fromthe disc-shaped crystal substrate 12 in the present embodiment, a squarethat is larger than the square having its diagonal the same length asthe diameter of the disc-shaped crystal substrate 12 is cut out.Furthermore, four solar battery cells are divided from the center linesof each side of the solar battery cell 1. This technique enables foursolar battery cells, each having a notch 13 to form one corner with apartially removed beveled edge 14, to be taken from one disc-shapedcrystal substrate 12.

[0084] As an example, when the disc-shaped crystal substrate 12 has adiameter of 100 mm, the maximum size of a square 11 in the 100 mmdiameter circle is 70 mm×70 mm if the edge clearance requirement isignored. This square provides four 35 mm×35 mm cells, respectivelydelimiting solar battery cell areas of 1225 mm².

[0085] In comparison to this, for example, if the solar battery cell 1in the form of a square (84.8 mm×84.8 mm) having a diagonal of 120 mm iscut out and divided into four solar battery cells, a solar battery cellarea of 1690.5 mm² each having the beveled edge 14 in one corner can beobtained.

[0086] The most common substrate in the manufacture of solar batterycells for space vehicles using both silicon and gallium arsenide is around semiconductor material having a diameter of 100 mm. Although otherdiameter sizes, such as 75 mm, 125 mm, and 150 mm, can be cited, thetechnique described herein is applicable in a similar manner.

[0087]FIG. 12 is an assembly diagram of a solar battery in which aredisposed the solar battery cells 1 a, 1 b, 1 c obtained from thetechnique of the present embodiment.

[0088] If diodes 2 a, 2 b are disposed in the triangular notches 13 ofthe beveled edges 14 in the solar battery cells 1 a, 1 b, 1 cmanufactured according to the above-mentioned technique, each solarbattery cell and diode can be disposed in the same plane without gaps.

[0089] The solar battery connection bracket 8 a has rectangularprotrusions for connecting the front surface electrodes 4 a, 4 b, 4 c ofthe solar battery cell 1 a and the rear surface electrodes of the solarbattery cell 1 b, rectangular protrusions for connecting the rearsurface electrode of the solar battery cell 1 b and the front surfaceelectrode 6 a of the diode 2 a, and a comb shape formed from a connectorfor mutually connecting the respective protrusions. The solar batteryconnection bracket 8 b has a similar shape and structure and connectsthe front surface electrodes 4 d, 4 e, 4 f of the solar battery cell 1b, the rear surface electrode of the solar battery cell 1 c, and thefront surface electrode 6 b of the diode 2 b.

[0090] Furthermore, the rear surface electrode of the solar battery cellla and the rear surface electrode of the diode 2 a are connected by thediode connection bracket 3 a, the adjacent solar battery cell la and thesolar battery cell 1 b are connected in series by the solar batteryconnection bracket 8 a, and the solar battery cells 1 a, 1 b and thediode 2 a are connected in parallel by the diode connection bracket 3 a.In the same manner, the rear surface electrode of the solar battery cell1 b and the rear surface electrode of the diode 2 b are connected by thediode connection bracket 3 b, and the solar battery connection bracket 8b connects the solar battery cells 1 b, 1 c in series, to which thediode 2 b is connected in parallel.

[0091] Although applied to embodiment 1 in the description above, thesolar battery cells obtained from the technique of the presentembodiment can also be used to form the solar battery cells withbuilt-in diodes in embodiments 2 to 5.

[0092] Using the solar battery cells of the present embodiment, the areaof edge portions 15 a to 15 d (shown in FIG. 11) after cutting out thesolar battery cells from the disc-shaped crystal substrate 12 can beminimized. Furthermore, combining diodes with the notches 13 in the cutout solar battery cells can prevent wasted area from being createdwithin the solar battery cell module.

[0093] Embodiment 7

[0094]FIG. 13 shows the shape of the disc-shaped crystal substrate 12and the solar battery cell 1 when manufacturing the solar battery cellfrom the disc-shaped crystal substrate 12 in embodiment 7 of the presentinvention.

[0095] In the solar battery cell 1 of the present embodiment, leavingthe circular portions of the disc-shaped crystal substrate 12 withrespect to the solar battery cells of embodiment 6 increases theportions that are usable as solar battery cells when manufacturing fromthe initial crystal substrate material.

[0096] In FIG. 13 are shown two solar battery cells 1 cut out from onedisc-shaped crystal substrate 12 leaving circular portions at two shortedges. Edges portions 15 a, 15 b are cut at an angle of Θ from thecenter of the circle from the solar battery cell 1. The angle Θ isusually 60° or 90° but may also be 0° in some cases.

[0097] In the present embodiment, the portions corresponding to the edgeareas 15 c, 15 d (shown in FIG. 11) of the disc-shaped crystal substrate12 in embodiment 6 disappear.

[0098] As an example, when the disc-shaped crystal substrate 12 has adiameter of 100 mm, the maximum size of the square 11 in the 100 mmdiameter circle is 70 mm×70 mm if the edge clearance requirement isignored. Therefore, the solar battery cell 1 having a circular portionwith diameter of 50 mm and a cutting angle Θ delimits respective solarbattery cell areas of 3699 mm² when Θ=60°.

[0099] According to the description above, the usable area for solarbattery cells from the 100 mm diameter wafer is substantially improvedfrom the 4900 mm² area of the square solar battery cell of 70 mm×70 mmto 7389 mm₂, and the initial manufacturing cost can be substantiallyreduced.

[0100]FIG. 14 shows an example of an assembly diagram in which solarbattery cells having circular portions are effectively disposed in thesolar battery in the present embodiment.

[0101] The solar battery cells 1 a, 1 b, 1 c having circular portionsare disposed in the same plane with the linear long edge and the shortedge opposing each other. Below this row of solar battery cells isdisposed in a mutually fitting manner a row of solar battery cells withthe circular portions facing the opposite horizontal direction(indicated by dotted lines) so as to fill the space 13 of FIG. 13. Thediodes 2 a, 2 b are disposed so as to fill the clearance between therows of solar battery cells.

[0102] The solar battery connection bracket 8 a has rectangularprotrusions for connecting the front surface electrodes 4 a, 4 b, 4 c ofthe solar battery cell 1 a and the rear surface electrodes of the solarbattery cell 1 b, rectangular protrusions for connecting the rearsurface electrode of the solar battery cell 1 b and the front surfaceelectrode 6 a of the diode 2 a, and a comb shape formed from a connectorfor mutually connecting the respective protrusions. The solar batteryconnection bracket 8 b also has a similar shape and structure andconnects the front surface electrodes 4 d, 4 e, 4 f of the solar batterycell 1 b, the rear surface electrode of the solar battery cell 1 c, andthe front surface electrode 6 b of the diode 2 b.

[0103] Furthermore, the rear surface electrode of the solar battery cellla and the rear surface electrode of the diode 2 a are connected by thediode connection bracket 3 a, the adjacent solar battery cell la and thesolar battery cell 1 b are connected in series by the solar batteryconnection bracket 8 a, and the solar battery cell la and the diode 2 aare connected in parallel by the diode connection bracket 3 a. In thesame manner, the rear surface electrode of the solar battery cell 1 band the rear surface electrode of the diode 2 b are connected by thediode connection bracket 3 b, the solar battery cells 1 b, 1 c areconnected in series by the solar battery connection bracket 8 b, and thediode 2 b is connected in parallel with respect to the solar batterycell 1 b.

[0104] Although each solar battery cell and diode are connected in thepresent embodiment according to a mode similar to that of embodiment 1,embodiments 2 to 5 may also be applied.

[0105] As in the present embodiment, configuring a solar battery moduleby disposing the solar battery cells with circular portions enables theunused spaces of the solar battery module to be minimized. Furthermore,disposing the planar diodes further effectively utilizes the unusedspaces.

[0106] Furthermore, the solar battery cell can improve efficiency interms of initial manufacturing cost by eliminating the waste in thedisc-shaped crystal substrate 12, reducing the number of machiningprocesses for cutting from the disc-shaped crystal substrate 12, andincreasing the light receiving area on the solar battery cell module.

[0107] Finally, the shapes of the diodes used in common with all of theabove embodiments will be described. FIG. 15 shows the shapes of thediodes used in the present invention. FIGS. 15(a) to (c) representtriangular diodes, (d) to (f) represent quadrangular diodes, and (g) and(h) represent circular diodes. The thickness of each diode issubstantially the same as the thickness of the solar battery cell.

[0108] Although the isosceles right triangle of FIG. 15(a) is apreferable shape for the diode to be used in embodiments 1 to 7, thereare instances where the diode of FIG. 15(b) can minimize wasted spaceaccording to the shape of the disposed space of the diode when the shapeof the solar battery cell is changed.

[0109] Furthermore, when recognizing the wasted space near the diode asin embodiments 6 and 7, the diode shape is selected on the basis of,besides space utilization efficiency, the shape of the diode arrangementspace according to the arrangement method of the solar battery cells andsuch factors as the diode manufacturing cost, for example, and there areinstances where it is preferable to use the shapes of FIG. 15(c) to (f).

INDUSTRIAL APPLICABILITY

[0110] As described above, the solar battery relating to the presentinvention can reduce waste in the number of machining processes in theinitial manufacturing cost for cutting out the solar battery cells fromthe disc-shaped crystal substrate, cut the number of assembly processes,and further increase the light receiving surface on the solar batterycells.

What is claimed is:
 1. A solar battery comprising: planar first andsecond solar battery cells; a diode connected in parallel with saidfirst solar battery cell; a solar battery connection bracket forconnecting a front surface electrode provided on a front surface of saidfirst solar battery cell and a rear surface electrode provided on a rearsurface of said second solar battery cell and a front surface electrodeprovided on a front surface of said diode; and a diode connectionbracket for connecting a rear surface electrode provided on a rearsurface of said first solar battery cell and a rear surface electrodeprovided on a rear surface of said diode; said first solar battery celland said second solar battery cell are planar solar battery cells thatare substantially rectangular having four corners, at least one of saidcorners has a partially removed beveled edge, and said diode is disposedadjacent to the beveled edge in the area of the removed corner.
 2. Asolar battery cell according to claim 1, wherein said solar batteryconnection bracket comprises: at least one rectangular first connectorfor connecting said front surface electrode of said first solar batterycell and said rear surface electrode of said second solar battery cell;at least one rectangular second connector for connecting said rearsurface electrode of said second solar battery cell and said frontsurface electrode of said diode; and at least one rectangular thirdconnector for connecting said rear surface electrode of said first solarbattery cell and said rear surface electrode of said diode; said firstconnector and said second connector and said third connector areconnected on a side opposite to the light receiving surface of saidsolar battery cell.
 3. A solar battery comprising: planar first andsecond solar battery cells; a diode connected in parallel with saidfirst solar battery cell; a first solar battery connection bracket forconnecting the front surface electrode provided on the front surface ofsaid first solar battery cell and the rear surface electrode provided onthe rear surface of said second solar battery cell; a second solarbattery connection bracket for connecting said rear surface electrode ofsaid second solar battery cell and the front surface electrode providedon the front surface of said diode; and a diode connection bracket forconnecting the rear surface electrode provided on the rear surface ofsaid first solar battery cell and the rear surface electrode provided onthe rear surface of said diode; said first solar battery cell and saidsecond solar battery cell are planar solar battery cells that aresubstantially rectangular having four corners, at least one of saidcorners has a partially removed beveled edge, and said diode is disposedadjacent to the beveled edge in the area of the removed corner.
 4. Asolar battery, in which at least two solar battery cells with built-indiodes are adjacently disposed in succession including: a substantiallyrectangular and planar solar battery cell having four corners and abeveled edge formed by partially removing at least one of the corners;and a diode disposed adjacent to the beveled edge in the area of theremoved corner; and in which front surface electrodes provided on frontsurfaces of the solar battery cell and the diode included in one solarbattery cell with built-in diode and rear surface electrodes provided onrear surfaces of the solar battery cell and the diode included inanother solar battery cell with built-in diode adjacent to said solarbattery cell with built-in diode are connected by one solar batteryconnection bracket.
 5. A solar battery, in which at least two solarbattery cells with built-in diodes are adjacently disposed in successionincluding: a substantially rectangular and planar solar battery cellhaving four corners and a beveled edge formed by partially removing atleast one of the corners; and a diode disposed adjacent to the bevelededge in the area of the removed corner; and in which front surfaceelectrodes provided on the front surface of the solar battery cellincluded in the solar battery cell with built-in diode and rear surfaceelectrodes provided on the rear surface of the solar battery cellincluded in another solar battery cell with built-in diode adjacent tosaid solar battery cell with built-in diode are connected by a solarbattery connection bracket; and surface electrode provided on the frontsurface of the diode included in the solar battery cell with built-indiode and rear surface electrode provided on the rear surface of thesolar battery cell and the diode included in another solar battery cellwith built-in diode adjacent to said solar battery cell with built-indiode are connected by a diode connection bracket.
 6. A solar batterycell as in one of claims 1-5, wherein said solar battery connectionbracket or said diode connection bracket is made of a material thatincludes silver.
 7. A solar battery cell as in one of claims 1-6,wherein said front surface electrode or said rear surface electrode ofsaid solar battery cell, or said front surface electrode or said rearsurface electrode of said diode includes silver.
 8. A solar battery cellas in one of claims 1-7, wherein said solar battery connection bracketor said diode connection bracket has a bend as a thermal expansionbuffer.
 9. A solar battery cell according to claim 8, wherein said bendhas a U-shaped structure.
 10. A solar battery cell as in one of claims1-9, wherein only one of said corners has a beveled edge.
 11. A solarbattery cell as in one of claims 1-10, wherein said beveled edge isformed from an arc.
 12. A solar battery cell as in one of claims 1-11,wherein said solar battery cell is cut out from a disc-shaped crystalsubstrate.